1. Field Of The Invention
The invention relates to a high aspartame content powder and/or granular aspartame sweetener with convenient to use physical properties and low cost features.
2. Description Of Related Art
Aspartame powder is dusty, unflowable, static, and is difficult to wet and disperse in water. It typically takes 5 minutes or longer to dissolve aspartame in room temperature water. Since aspartame is only slightly soluble in water (.noteq.1% solubility in room temperature water), its dissolution rate decreases sharply with increasing particle size. Pure aspartame granule made by roll compaction methods are very slow to dissolve in water. Even with fine granular particles, e.g., 80-140 mesh size aspartame particles typically take more than 5 minutes to dissolve in room temperature water.
A major application of aspartame is for use as a table-top sweetener. The most popular aspartame table-top sweeteners are packet, tablet, and spoon-for-spoon bulk table-top sweeteners. Aspartame tablets are slow to dissolve and are not convenient for use in cold drinks. Besides, it can not be conveniently portioned. The spoon-for-spoon bulk sweetener is made by a very expensive process which spray-dries dilute, .noteq.3%, hot aspartame water solution containing bulking agents such as maltodextrin. Such a product is very light, bulky, and hygroscopic, and are very expensive to package, ship, and store. The most popular table-top aspartame product is in packet form. This packet product typically has one gram of aspartame and bulking agent and has a sweetening power equivalent to 1 or 2 teaspoons of sugar. The packet contains 1.5-4% aspartame and 96-98.5% bulking agent, such as dextrose and maltodextrin. Even though the caloric content for the amount of aspartame used in a packet product is neglegibly small, an aspartame packet contains 4 calories mainly from its bulking agent. Besides increasing both cost and caloric content, a high bulking agent content product is hygroscopic which shortens the shelf life of aspartame in the product. There is, therefore, a need to improve aspartame table-top sweetener products.
Aspartame can not be used directly as a table-top sweetener like granular sugar, since the above mentioned poor physical properties make it too difficult to measure, to handle and to dissolve a small amount of aspartame needed to sweeten a glass of beverage. A variety of granulation methods have been proposed to overcome the above discussed problems of powder aspartame. These methods teach that aspartame must be granulated with a high percentage of bulking agents, e.g. over 50% composition, to obtain a fast-dissolving granular aspartame product. Since soluble bulking agents such as dextrose and maltodextrins are hygroscopic, the high bulking agent content granular aspartame products are also hygroscopic and are not ideal for use as table-top sweeteners.
Due to its high sweetening potency, many applications need to use fine particulate aspartame instead of granular aspartame. It is difficult to make powder and fine granular aspartames which have good flow, low dust, and fast dissolving properties. U.S. Pat. No 5,085,876 to Tsau teaches the use of a small amount of Caramel color to greatly enhance the dissolution rate of powder and granular aspartame. This patent, however, does not address aspartame's dust and flow problems.
Commercial aspartame packet products, such as the product Equal, mix a small amount of aspartame, .noteq.1.8%-4%, with a large amounts, .noteq.96%-98%, of fast-dissolving fast-flowing granular bulking agent, such as granular dextrose or granular maltodextrin to obtain a fast-dissolving and free-flowing table-top packet aspartame sweetener. This proves that, in water, dispersed fine aspartame powder particles are actually fast dissolving. Such a high bulking agent content product, however, is both expensive and hygroscopic and has significant amount of caloric content, 4 cal/packet. Further, part of the aspartame, from .noteq.3% to .noteq.25% of the total aspartame content, in this type of product clings on the inner wall of the packet becoming unavailable for sweetening uses.
Besides low dust, low hygroscopicity, and being fast-dissolving, an ideal table-top granular aspartame sweetener should have dust-free hard particles. It should also have excellent flow characteristics for both high-speed packaging to make low cost packet products and for easy pouring from containers such as a shaker or packet for table-top sweetening applications. In addition, it should be ideal for an aspartame table-top sweetener product to have less than 0.5 calorie per serving so that a zero calorie claim can be made.
Some of these ideal properties do not co-exist easily. For example, the larger the granular particles the less dusty the product is. Increasing the granular particle size, however, usually greatly reduces a particle's dissolution rate. It is also generally true that increasing a particle's hardness reduces dust but also retards dissolution rate. Spherically shaped granular particles have an optimum flow character but the lowest dissolution rate due to the fact that they also have the smallest surface area. It should be surprising that an aspartame sweetener can be made to have all the above mentioned ideal properties.
Spherical fat-encapsulated granular aspartame can be made by spray-congealing hot-melt fat dispersed with aspartame. It is a water-insoluble product useful in baked goods to stabilize aspartame during baking. Spherical granular aspartame can also be made in a centrifugal force granulator such as the CF granulator made by Vector Co. and an extrusion-spheronization method. None of these methods are known to make spherical granular aspartame with a fast dissolution rate.